The major goals are to continue and extend research on: (1) risk and protective factors involved in onset, stability and change in adolescent drug use; (2) testing pathways to drug use; (3) interactive effects of risk and protective factors; and (4) consequences of drug use on adolescent and young adult functioning. The proposed research will expand on and extend prior research by: (1) inclusions of samples of inner city youngsters and IV drug abusers; (2) comparisons of the etiologies of drug use, delinquency, psychopathology, and sexual precocity; (3) study of intra- and intergenerational transmission of drug-prone characteristics; and (4) examination of factors related to AIDS transmission behavior and to coping with AIDS. In order to achieve these goals, an integrated program of research is underway involving four large-scale projects: I. A longitudinal study of approximately 1000 children and their mothers seen at four points in time from ages 1-10 to 15-24; II. A multigenerational study of 250 two-year old offspring of the original study child in Project I; III. A study of about 1600 inner city Black and Puerto Rican adolescents (including a school drop-out sample); IVA. A study of 400 male HIV+ and HIV- intravenous drug users; and IVB. A study of 400 female HIV+ and HIV- intravenous drug users. The major significance of this program of integrated research is that it addresses many critical issues in the drug field, e.g., what can protect against these risks; how do risk and protective factors operate in populations most likely to become involved in drug or other problem behaviors, including those implicated in the spread of AIDS; how can one break the transmission of the risk from one generation to the next; and how can the consequences of drug use be averted or lessened.